Denial

I believe this is the right board index to ask the following question:

I am looking for the Basic ROM of my VIC20, I get just a blue border and not characters and changing colors, a game cartridge shows characters, so my troubleshooting directs me to the Basic ROM, any has one for sale ?

I bought a couple of these recently, not sure if they ship to you

https://www.ebay.co.uk/itm/901486-01-VI ... Sw55dgSMyh

If not PM me and we can discuss me shipping one to you.

I have just order one from this guy also, to be sent to my relatives UK address, have you tested them and they work ?

Botialoach wrote: ↑Sun Mar 28, 2021 12:56 pm I have just order one from this guy also, to be sent to my relatives UK address, have you tested them and they work ?

Only tested one, worked fine.

Botialoach wrote:I get just a blue border and not characters and changing colors, a game cartridge shows characters, so my troubleshooting directs me to the Basic ROM, any has one for sale?

This error pattern can also appear with a fault of the internal RAM. The KERNAL executes a RAM check and ends up in a spin loop when bad internal RAM (in the $1000 to $1FFF range) is detected. Cartridge code is autostarted before the RAM check commences and many game cartridges omit a RAM check in their own continued reset sequence, so they start through but are oblivious of any RAM issues and might show unexpected behaviour (like graphics display errors, game logic glitches or crashes) later in-game.

In advance to exchanging the BASIC ROM, check out if any of the RAM chips gets exceedingly hot and replace that one first.

Does the VIC 20 short board , take the same RAM chips as the C64 i.e. the 4164 20ns, if so, I can picky back them to see if the problem is solved correct?

Botialoach wrote: ↑Tue Apr 20, 2021 5:53 am Does the VIC 20 short board , take the same RAM chips as the C64 i.e. the 4164 20ns, if so, I can picky back them to see if the problem is solved correct?

No. The original takes 2114s (1K x 4 SRAM) and the CR a mix of 2114s and 2016s (2K x 8 SRAM).

My Vic 20 board is 250403, so it takes the 2114 and 2016 RAM, also I noticed that if I insert a game cartridge it shows all the letter and number with out any problem. Everything look right. Since I have no RAM to picky back , my only option is to wait for the Basic ROM to arrive and hope it solved the problem ?
Am I down the correct path?

Unless you're able to burn your own EPROM with a memory tester I think you'll have to wait for BASIC ROM. If the game cartridge plays with no crashes or screen corruptions there's a good chance the ROM is at fault.